iOS通过点坐标获取js对应元素

   //模拟屏幕上的某一点
    CGFloat x = mainS.width/2,y = mainS.height/2-352;
    
    //js获取点元素字符串
    NSString *jsn = [NSString stringWithFormat:@"document.elementFromPoint(%f, %f).tagName", x, y];
    
    //通过加载js获取点对应节点元素名称
    NSString * tagName = [_webView stringByEvaluatingJavaScriptFromString:jsn];
    
    NSLog(@"%@",tagName);
    
    //获取对应元素并对其进行操作的字符串
    NSString * jsee = [NSString stringWithFormat:@"var obj = document.elementFromPoint(%f, %f); alert(obj);var event = {clientX:%f,clientY:%f};obj.click(event)",x,y,x,y];
    
    //加载字符串实现要的效果
    [_webView stringByEvaluatingJavaScriptFromString:jsee];